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Acne: Overview

Last Update: January 30, 2013; Next update: 2016.


Nearly every teenager will discover their first pimple at some point. Some only get single pimples that clear up again quickly. Others develop more severe, persistent and clearly visible acne. That can be very distressing, particularly in puberty. But there are a number of things that can be done about acne, although the treatments require patience. This information is about acne in teenagers and young adults called “common acne or acne vulgaris.


Acne is more severe in some people than in others. Doctors distinguish between mild, moderate and severe forms of acne. There are also inflammatory and non-inflammatory types of acne. Non-inflammatory acne is a milder type, which most people would refer to as “pimples” or “blackheads” rather than “acne.”

Unlike normal pimples, acne develops over a longer period of time and stays longer. It sometimes leaves small red marks or scars behind. “Normal” pimples usually form quickly and then disappear again soon afterwards.

  • Mild acne: People with mild acne have comedones (blackheads or whiteheads), which are clogged pores in the skin. The dark color of blackheads has nothing to do with dirt: They look dark because this kind of blackhead is “open,” and the skin pigment melanin reacts with oxygen in the air. Whiteheads are closed, and have a white or yellowish head. The more the oil builds up, the more likely it is that bacteria will multiply and lead to inflammatory acne. Acne is also considered to be “mild acne” if someone only has a few pimples, or small ones.
  • Moderate acne: People who have moderate acne have noticeably more pimples. Inflamed pimples are called “papules” (small bumps) or “pustules” (filled with yellow pus).
  • Severe acne: People who have severe forms of acne have a lot of papules and pustules, as well as nodules on their skin. These nodules are often reddish and painful, and can cause scarring.


Puberty is the time when a child’s body changes to the body of an adult. This change is regulated by hormones such as androgen. Androgen is a male sex hormone which is made in larger amounts during puberty – in girls too. One thing that it does is make your skin produce more oil.

Structure of healthy skin, including oil glands

The oil that is made in the skin is called sebum, and it is produced in oil glands referred to as sebaceous glands. Sebum has an important function: It protects the outermost skin layer and helps to keep it moisturized. But if a layer of dead cells builds up at the opening of a pore, the sebum cannot be released. The oil builds up in the skin, forming a comedone (blackhead or whitehead). If this becomes inflamed, it turns into a pimple (also called zits or spots). Acne mostly develops on areas of skin that have more oil glands, like the face, chest, back and shoulders.

The main reason teenagers get acne is because their bodies make more of the hormone androgen during puberty. Once their hormone levels have settled down, typically by their early twenties, acne usually goes away on its own. But not all teenagers have acne, so it is believed that other things play a role too, such as genetic factors and the immune system

Development of a pimple

Risk factors

There are a lot of theories about what might make acne more likely. Some of these ideas are supported by scientific proof, but many are not. For instance, people sometimes say that you get acne, or that it gets worse, if you do not wash properly. There is no scientific proof that this is true. But claims like this can make teenagers feel guilty because they believe having acne is their own fault.

Some people think that their acne gets worse if they eat particular foods, like chocolate, meat or dairy products. A number of scientific studies have looked into the effect of diet on acne, but they did not find any connection between what people eat and the likelihood that they develop acne.

Some skin care products, such as moisturizing creams or oils that might block skin pores, can make acne worse. Rubbing your skin too hard or squeezing blackheads can have the same effect.

Some people report that their acne gets worse when they are under a lot of pressure. Scientific studies also suggest that there is a link here. It is not clear whether there might be a connection between smoking and acne.

Hormones are not only produced by the body. They can be found in some medications and other products too. This means that there are some hormone treatments that can cause acne or make it worse. These include anabolic substances and medications such as steroids, as well as some drugs for treating epilepsy.


Acne is the most common skin condition in teenagers. Most people will have acne to some degree during puberty. About 15 to 20 out of 100 teenagers have moderate to severe acne. It is much more common in boys than in girls.


Acne often clears up on its own at around the age of 20, but some people still have acne when they are over the age of 30. Scars or red marks – and brownish marks on darker skin – may remain.


Acne can lead to scarring, especially if it is severe. Scars can form when wounds heal. The wounds caused by acne are found in the deeper layers of skin and they can heal in very different ways. Whereas some people only have small, flat scars that are hardly noticeable, others have clearly visible indented scars (“pock marks”) on their face. Acne scars can be divided into the following categories:

  • Atrophic scars: If an acne wound does not heal properly, not enough connective tissue is made. The scar then forms beneath the surrounding tissue, creating a dent in the skin. People who do not squeeze their pimples are less likely to get these scars.
  • Hypertrophic scars: These raised scars can form on your chest, back or shoulders, particularly in people who have severe acne. They develop if too much connective tissue is produced while the wound is healing. This type of acne scar is less common.
  • Keloid scars: Keloid scars also form when too much connective tissue is made. Unlike hypertrophic scars, however, they are bigger than the original inflamed area. This is a very rare type of acne scarring.

Regularly squeezing blackheads and pustules can increase the likelihood of scarring.


People with acne often try out different things to improve the appearance of the skin. There are a lot of different recommendations when it comes to acne: Face lotions, sunlight and specific diets being some of them.

There are a number of medical treatments available for treating acne - creams and lotions as well as tablets. Many of the products are heavily marketed because you do not need a prescription to purchase them, but the advertising campaigns often create unrealistic expectations. Some treatment approaches and medications have been proven to effectively reduce acne, while others have not.

Unfortunately there are only a few good-quality studies comparing the various treatments with each other. So it is often not possible to know whether certain products are more effective than others. Most products have to be taken for a long time before there is noticeable improvement. And some have strong side effects.

Everyday life

Puberty is a difficult time of life. Many teenagers may feel less self-confident, and be very negative about themselves and their appearance. This is especially true of teenagers who have acne, who often feel unattractive or might be embarrassed about how they look. The severity of someone’s acne does not always directly determine how big of an emotional problem it is. Moderate acne can be just as distressing as severe acne.

How people cope with acne varies widely. Some are less bothered by it or can deal with it in a more self-confident way, but for others it can be a major problem. Anxiety, depressive thoughts, low self-esteem and social withdrawal are more common in people who have acne. They are more likely to have conflicts with their family and friends too.

Comments people make about their skin condition can be very upsetting, and difficulties finding a boyfriend or girlfriend might be hard to take. But mood swings are a normal part of puberty, even in teenagers who do not have acne. So it would be wrong to blame all puberty-related problems and mood swings on acne.

Because having acne can make teenagers feel less self-confident around others, supportive friends and family are particularly important. Things like foundation and concealer can make it easier to cope with acne in everyday life if it helps someone feel more confident in public.


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IQWiG (Institute for Quality and Efficiency in Health Care)

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